What is schedule s? And why is it making me file it?

Is this a federal schedule or a state schedule that needs to included in your tax return?   If a state, which state?

In the Review section of the program you will see any forms or schedules that need to be finalized and estimated date they will be available.

Are you talking about state or federal, business or personal.  Schedule S for federal is for foreign income exclusion from international operation of ships and aircraft.  This is not common. 

If you it is asking for one from the state, we would need to know which state you are in as different states have different forms.